Oxidation- and thermo-responsive poly(N-isopropylacrylamide-co-2-hydroxyethyl acrylate) hydrogels cross-linked via diselenides for controlled drug delivery

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4162-4170 ◽  
Author(s):  
Xinfeng Cheng ◽  
Yong Jin ◽  
Tongbing Sun ◽  
Rui Qi ◽  
Baozhu Fan ◽  
...  

A novel diselenide crosslinked poly(NIPAM-co-HEA) hydrogel was successfully synthesized, which exhibits a dual-stimuli-responsive drug release behaviors,i.e., thermo-induced slow sustained release and oxidation-induced quick burst release.

2017 ◽  
Vol 32 (5) ◽  
pp. 469-486 ◽  
Author(s):  
Gang Zhou ◽  
Jing Zhang ◽  
Jun Tai ◽  
Qianyi Han ◽  
Lei Wang ◽  
...  

The development of controlled drug delivery systems for bone regeneration, especially microspheres, has become a research hotspot in recent years. Chitosan and its derivative O-carboxymethyl chitosan have been considered to be an effective way for controlled drug delivery due to their nontoxicity and biodegradability. Currently, most of the studies have researched on synthesizing and characterizing chitosan and O-carboxymethyl chitosan. However, few studies have focused on the differences between chitosan microspheres and O-carboxymethyl chitosan microspheres directly. In this study, chitosan and O-carboxymethyl chitosan microspheres were developed by water-in-oil emulsification cross-linking method using vanillin as the cross-linking agent, and then their physicochemical properties were evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy, and in vitro release testing. The results showed that O-carboxymethyl chitosan was successfully modified by adding carboxymethyl group at the chitosan C6 position.The particle size of chitosan microspheres (50–90 µm) was significantly larger than that of O-carboxymethyl chitosan microspheres (10–50 µm), and the drug release profile of O-carboxymethyl chitosan microspheres showed larger initial burst release within the first day and sustained release at the fourth day, while chitosan microspheres showed sustained release at the seventh day. In addition, Cell Counting Kit-8 assay showed that MC3T3-E1 proliferated well and highly expressed the alkaline phosphatase marker protein on both chitosan and O-carboxymethyl chitosan microspheres. Overall, both chitosan and O-carboxymethyl chitosan microspheres showed good biocompatibility, and chitosan microspheres were superior to O-carboxymethyl chitosan microspheres. Moreover, the different drug release rates suggest that chitosan and O-carboxymethyl chitosan microspheres have the potential to be used for the repair of different bone defects.


2012 ◽  
Vol 62 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Martins Emeje ◽  
Lucy John-Africa ◽  
Yetunde Isimi ◽  
Olobayo Kunle ◽  
Sabinus Ofoefule

Eudraginated polymer blends: A potential oral controlled drug delivery system for theophylline Sustained release (SR) dosage forms enable prolonged and continuous deposition of the drug in the gastrointestinal (GI) tract and improve the bioavailability of medications characterized by a narrow absorption window. In this study, a new strategy is proposed for the development of SR dosage forms for theophylline (TPH). Design of the delivery system was based on a sustained release formulation, with a modified coating technique and swelling features aimed to extend the release time of the drug. Different polymers, such as Carbopol 71G (CP), sodium carboxymethylcellulose (SCMC), ethylcellulose (EC) and their combinations were tried. Prepared matrix tablets were coated with a 5 % (m/m) dispersion of Eudragit (EUD) in order to get the desired sustained release profile over a period of 24 h. Various formulations were evaluated for micromeritic properties, drug concentration and in vitro drug release. It was found that the in vitro drug release rate decreased with increasing the amount of polymer. Coating with EUD resulted in a significant lag phase in the first two hours of dissolution in the acidic pH of simulated gastric fluid (SGF) due to decreased water uptake, and hence decreased driving force for drug release. Release became faster in the alkaline pH of simulated intestinal fluid (SIF) owing to increased solubility of both the coating and matrixing agents. The optimized formulation was subjected to in vivo studies in rabbits and the pharmacokinetic parameters of developed formulations were compared with the commercial (Asmanyl®) formulation. Asmanyl® tablets showed faster absorption (tmax 4.0 h) compared to the TPH formulation showing a tmax value of 8.0 h. The Cmax and AUC values of TPH formulation were significantly (p < 0.05) higher than those for Asmanyl®, revealing relative bioavailability of about 136.93 %. Our study demonstrated the potential usefulness of eudraginated polymers for the oral delivery of the sparingly soluble drug theophylline.


2021 ◽  
Vol 11 (20) ◽  
pp. 9541
Author(s):  
Zhichu Xiang ◽  
Mouquan Liu ◽  
Jun Song

Biocompatible nanosystems based on polymeric materials are promising drug delivery nanocarrier candidates for antitumor therapy. However, the efficacy is unsatisfying due to nonspecific accumulation and drug release of the nanoparticles in normal tissue. Recently, the nanosystems that can be triggered by tumor-specific stimuli have drawn great interest for drug delivery applications due to their controllable drug release properties. In this review, various polymers and external stimuli that can be employed to develop stimuli-responsive polymeric nanosystems are discussed, and finally, we delineate the challenges in designing this kind of Nanomedicine to improve the therapeutic efficacy.


RSC Advances ◽  
2020 ◽  
Vol 10 (46) ◽  
pp. 27305-27314
Author(s):  
Yolanda Salinas ◽  
Michael Kneidinger ◽  
Cristina Fornaguera ◽  
Salvador Borrós ◽  
Oliver Brüggemann ◽  
...  

Bottle-brush polyphosphazenes as dual, thermosensitive and pH responsive gatekeepers for mesoporous silica nanoparticles, and their use in controlled drug release.


1995 ◽  
Vol 18 (8) ◽  
pp. 1154-1158 ◽  
Author(s):  
Motoko KANKE ◽  
Emi TANABE ◽  
Hirokazu KATAYAMA ◽  
Yoko KODA ◽  
Hironori YOSHITOMI

Author(s):  
Feng Wu ◽  
Fei Qiu ◽  
Siew Anthony Wai-Keong ◽  
Yong Diao

Background: In recent years, the emergence of stimuli-responsive nanoparticles makes drug delivery more efficient. As an intelligent and effective targeted delivery platform, it can reduce the side effects generated during drug transportation while enhancing the treatment efficacy. The stimuli-responsive nanoparticles can respond to different stimuli at corresponding times and locations to deliver and release their drugs and associated therapeutic effects. Objective: This review aims to inform researchers on the latest advances in the application of dual-stimuli responsive nanoparticles in precise drug delivery, with special attention to their design, drug release properties, and therapeutic effects. Syntheses of nanoparticles with simultaneous or sequential responses to two or more stimuli (pH-redox, pH-light, redoxlight, temperature-magnetic, pH-redox-temperature, redox-enzyme-light, etc.) and the applications of such responsivity properties for drugs control and release have become a hot topic of recent research. Methods: A database of relevant information for the production of this review was sourced, screened and analyzed from Pubmed, Web of Science, SciFinder by searching for the following keywords: “dual-stimuli responsive”, “controlled release”, “cancer therapy”, “synergistic treatment”. Results: Notably, the nanoparticles with dual-stimuli responsive function have an excellent control effect on drug delivery and release, playing a crucial part in the treatment of tumors. They can improve the encapsulation and delivery efficiency of hydrophobic chemotherapy drugs, combine chemo-photothermal therapies, apply imaging function in the diagnosis of tumors and even conduct multi-drugs delivery to overcome multi-drugs resistance (MDR). Conclusion: With the development of smart dual-stimuli responsive nanoparticles, cancer treatment methods will become more diverse and effective. All the stimuli-responsive nanoparticles functionalities exhibited their characteristics individually within the single nanosystem.


2020 ◽  
Vol 11 (19) ◽  
pp. 3296-3304
Author(s):  
Jinkang Dou ◽  
Ruiqi Yang ◽  
Kun Du ◽  
Li Jiang ◽  
Xiayun Huang ◽  
...  

Ultrasound-controlled drug release is a very promising technique for controlled drug delivery due to the unique advantages of ultrasound as the stimulus.


2021 ◽  
Vol 9 (1) ◽  
pp. 38-50
Author(s):  
Hien Phan ◽  
Vincenzo Taresco ◽  
Jacques Penelle ◽  
Benoit Couturaud

Stimuli-responsive amphiphilic block copolymers obtained by PISA have emerged as promising nanocarriers for enhancing site-specific and on-demand drug release in response to a range of stimuli such as pH, redox agents, light or temperature.


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